Electrically-operated piano-player.



W. C. REED.

ELECTRICALLY OPERATED mm) PLAYER.

APPLlCATION FILED IAN-29. I913.

Patented J an. 9, 1917.

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WALTER C. REED, OF DALTON, MASSACHUSETTS, ASSIGNOR TO THE TELELECTRIC COMPANY, OF PITTSFIELD, MASSACHUSETTS, A CORPORATION OF MASSACHU- SETTS.

ELECTRICALLY-OPEBATED PIANO-PLAYER.

Application filed January 29, 1913.

Toall whom it may concern Be it known that I, WALTER C. Reno, aciti- Zen of the United States, residing at Dalton in the county of Berkshire and State of Massachusetts, have invented new and useful Im rovements in Electrically-Operated IianoIlayers, of which the following is a specification.

In U. S. Letters Patent No. 1,152,841, granted Sept. 7th, 1915, I have shown and described an electrically-operated piano-playing apparatus in which the loudness of the tones produced by a predetermined number or group of playing magnets is regulated by means of a single resistance which is included in a common portion of the energizing circuit for said magnets and is automatically varied in such manner that the current sent through each playing magnet is substantially maintained at What may be termed its normal strength, regardless of the number of magnets in closed circuit at one time, provision being made for varying the normal current strength either automatically or manually or in both ways in order to produce the desired expression efiects in the composition played.

My present invention is herein described as embodied in a playing apparatus havin the general characteristics above referre to, being particularly intended to improve upon the subject matter of my aforesaid patent in certain respects which are hereinafter set forth. 3

The accompanying drawings illustrating my invention are diagrammatic in character, as the construction of the various parts employed will be readily understood without specific illustration of the details.

In these drawings: Figure 1 is a diagram showing my preferred arrangement of such of the circuits and other parts of the aparatus as will sufiice for exemplifying my improvements, and Fig. 2 shows in somewhat more detail an arrangement for securing general regulation of the loudness of the tones produced.

The parts indicated in Fig. 1 of the drawings include a metallic contact bar 2, circuitcontrolling fingers 3 adapted to make contact with the bar 2 independently of one another when permitted to do so by the music sheet which controls their operation, a playing magnet 4 in series with each-finger 3, a circuit wire 5 leading from the contact Specification of Letters Patent.

Patented Jan. 9, 1917.

Serial No. 744,814.

bar to one terminal of a suitable generator 6 and including a starting and stopping switch 7, and a common return Wire 8 leading from the other terminal of the generator 6 to the playing magnets through connections hereinafter described. In the arrangement herein represented the playing magnets 4 are divided into two groups corre sponding respectively to the base and treble notes of the keyboard, two magnets of each group being represented, and all the mag nets of each group are provided with a com mon return circuit Wire 9. All of the abovemention'ed parts may be of well-known construction.

Each group of playing magnets has associated with it a variable resistance which serves for regulating the loudness of the notes struck by all the magnets in that group, and since the resistances and associated parts corresponding to the two groups of playing magnets are identical in construction and arrangement the following description of one set of these parts will apply as well to the other set. In the example herein represented said resistance, shown at 10, is made up of a number of equal portions which are arranged in parallel with one another and are each connected at one end to a corresponding insulated segment 11 and at the other end to a circuit wire 12 which is common to all the resistance portions, the collective segments 11 being arranged in the form of a bar. Each of these resistance portions should have such length that it will transmit not more than enough current (preferably just enough current) to produce the softest tone required when but one playing magnet in the corresponding group is in closed circuit. The circuit through the resistance 10 includes a contact finger 13, which is adapted to slide along the segment bar and is so shaped that it can make simultaneous contact'with a number of the segments 11 and thereby vary the amount of resistance included inthe common return circuit of the corresponding group of playing magnets, said finger 13 being connected by a flexible circuit wire 14 to the common return wire 9 and the circuit wire 12 being connected to the common return wire 8.

As described thus far, the a paratus is of apparatus are also similar in this respect, that the movable contact finger is operated by an electromagnet and an opposed spring in such manner that the resistance is automatically varied substantially in inverse proportion to the number of playing magnets in the corresponding group which are in closed circuit at one time, thereby maintaining the normal strength in the current sent through each magnet. In the other form of the apparatus, however, the controller magnet has a negligible resistance and is connected in series with the common return portion of the playing magnet circuits, whereas in the present form of my apparatus the controller magnet, indicated at 15, has a relatively hi h resistance and is connected across the rop, i. e., it is so related to the total load circuit (consisting substantially of the playing magnets) that it is affected by changes in the difference of potential between the terminals of the load circuit. In-the example represented, circuit wires 16 and 17 lead respectively from the contact bar 2 to the controller magnet 15 and from said magnet to the common return wire 9, so that the controller magnet circuit is in parallel with the circuits of the playing magnets in the corresponding group. The resistance of the controller magnet 15 should be at least equal to that of one playing magnet, and may be considerably greater, inlorder that said magnet may use but little current and may be sensitive to slight changes in the difference of potential between the opposite terminals of the playing magnet coils. Said controller magnet is preferably of the solenoid type, and the contact finger 13 is carried by its lunger armature 18, which is drawn into t e coils of the magnet against the pressure of a compression spring 19 bearin at one end against the r lunger and at its other end against an a justable abutment 20, the construction and arrangement of these parts being such that whenever the magnet 15 is weakened and its plunger 18 is forced outward, the contact finger 13 is moved thereby insuch direction asrto make contact with an increasing number of the segments 11, as hereinafter explained.

operation of the parts above described, which will be explained with reference to a single group of playing magnets widen the assumptionthat the parts are so adjusted as to cause the piano keys to give the softest tone r uired, is as follows: 80 long as the energizing circuit is open at the switch 7 the controller magnet 15 receives no current and the spring 19 forces the lunger l8 and the contact finger 13 to the imit of their outward movement. If mow the circuit is closed at the switch 7 the controller magnet will receive the maximum voltage to which it is subjected, assuming that no playin magnet is in closed circuit, and will there ore exert its maximum effect and draw its plunger inward against the increasing force of the spring 19, which spring is so calibrated that when a position of rest is reached by the contact linger 13 under these conditions the latter is in contact with that end segment 11 which is nearest the magnet 15. 'lliereaftcr, whenever the circuit through one or more of the playing magnets is closed the strength of the current sent through the controller magnet 15 is correspondingly weakened, with the result that the spring 19 forces the plunger 18 outward and causes the contact finger 13 :to move along the segments 11 until the decreasing efiect of said spring is balanced by the pull of the magnet 15, and these parts are so designed that by such movement of the finger 13 the efiect of the resistance 10 is sufficiently reduced to maintain the normal current strength through such playing magnets as are in closed circuit at that time.

It will be evident that if each of the parallel portions of the resistance 10 is designed to transmit just enough current to actuate one playing magnet with the minimum force required, the contact finger 13 should not move beyond the end segment above referred to when the circuit through one playing'magnet only is closed, and in order to provide for the slight movement of said finger 13 under such conditions the end segment may be sulficiently elongated, as shown, to extend over the range of movement of the finger 13 between its extreme position and the position which it takes when the circuit is closed through a single playing magnet only.

The resistance-varying arrangement above described has the advantages, as contrasted with the arrangement shown in my aforesaid patent, that the controller-magnet is always in closed circuit during the operation of the apparatus and therefore has its magnetism somewhat built up at all times, and that the resistance-decreasing movement of the contact finger is effected by the weakening of the controller-magnet, thereby causing the compression spring tooperate said contact finger. This results in greater sensitiveness and quickness of operation of the contact finger when the load changes, and the maintenance of the desired normal current is thus effected with greater certainty and accuracy.

For varying the normal current strength to produce different tone effects any or all of the various arrangements described in my prior patent may be employed, and by way of example I have shown herein an arrangement commonly utilized for providing for general regulation of the loudness of the tones produced. As shown in Fig. 2

the Segment bar, which is assumed to be capable of sliding in an endwise direction, is connected to a bar 22 adapted to be moved longitudinally by one or another of a group of electro-magnets 23, the circuits through which are under the control of the music sheet, or by means of a manually operated hand wheel 24 carrying an arm 25 with a slot 26 therein which receives a pin 27 con nected to the bar 22. The parts just described enable the segment bar to be shifted longitudinally with respect to the contact finger 13 independently of the automatic movements of the latter, the result of doing this being to out in or out more or less of the resistance and thereby vary the normal strength of the current. This arrangement is like that employed for the same purpose in the apparatus shown in my patent previously mentioned, and requires that the number of segments 11 be sullicient to pro ride 'a' range of movement for the contact linger 13 such as will enable the latter to cll'ect the automatic regulation of the resistaiu-c in all positions of the segment bar. In the example herein represented ten of the scjnucnts 11 are employed, each connected to a corresponding portion resistance 10,but the number of such segments may be varied as desired, having regard to the fact that if it takes more than one of the resistance portions 10 to transmit enough current for a single playing magnet, the number of these portions 10 must be correspondingly in creased.

It is to be understood that it is not at all essential that the resistance portions above referred to be arranged in parallel with one another, or that the playing magnets be derided into two groups, since these and the other details herein described may be widely varied without departing from my present invention, the distinctive characteristic of which is the automatic regulation of the current strength by means of a controllermagnet connected across the drop.

I claim as my invention 1 1. An electrically-operated piano player comprising a series of playing magnets arranged in parallel circuits, means for closing the circuits through the several magnets according to the notes to be played thereby, a controller magnet included in a normally closed circuit arranged in arallel with the playing magnet circuits, an means operated by said controller magnet for substantially maintaining a predetermined strength inthe current sent through each one of such playing magnets as are in closed circuit at one time.

2. An electrically-operated piano player comprising a series of playing magnets arranged'in parallel circuits, means for closing the circuits through the several magnets according to the notes to be played thereby, a controller magnet included in a normally closed circuit arranged in parallel with the playing magnet circuits, means operated by said controller magnet for substantially maintaining a predetermined strength in the current sent through each one of such playing magnets as are in closed circuit at one time, and means for varying the predetermined current strength.

3. An electrically-operated piano player comprising a series of playing magnets arranged in parallel branches of a circuit having a portion which is common to all the magnets of the series, means for closing the branch circuits through the several magnets according to the notes to be played thereby, a resistance included in the common portion of the playing magnet circuit, and means for automatically varying said resistance comprising a controller magnet included in a normally closed circuit arranged in parallel with the playing magnets! 4'. An electricallyoperated piano player comprising a. series of playing magnets arranged in parallel branches of a circuit having a portion which is common to all the magnets of the series, means for closing the branch circuits through the several magnets according to the notes to be played thereby, a resistance included in the common portion of the playing magnet circuit, a controller magnet included in a normally closed circuit arranged in parallel with the playing magnets, means operated by the controller magnet for varying said resistance to such an extent as to substantially maintain a predetermined strength in the current sent through each one of such playing magnets as are in closed circuit at one time, and means for varying the predetermined current strength.

5. An electrically-o erated piano player comprising a series 0 playing magnets arranged in parallel branches of a circuit having a portion which is common to all the magnets of the series, means for closing the branch circuits through the several magnets according to the notes to be played thereby, a resistance included in the common portion of the playing magnet circuit, a solenoid included in a normally closed circuit arranged in parallel with the playing magnets, a plunger movable in one direction b said solenoid, a sprin for moving said p unger in the opposite irection, and means operated by the plunger for varying said resistance.

6. An electrically-o erated piano player comprising a series 0 playing magnets arranged in parallel branches of acircuit having a ortion which is common to all the magnets o the series, means for closing the branch circuits through the several magnets according to the notes to be played thereby, a resistance included in the common portion of the playing magnet circuit and divided into a ;number of portions arranged in parallel circuit with one another, and means for automatically varying said resistance comprisinga controller magnet included in a normally closed circuit arranged in parallel with the playing magnets.

7. An electrically-o erated piano player comprising a series 0 playing magnets arranged in parallel branches of a circuit having a portion which is common to all the magnetsrof the series, means for closing the branch circuits through the several magnets according to thenotes to be played thereby, a resistance divided into a number of portions, a segment bar having its segments connected with the resistance portions respectively, a contact finger movable along said bar, circuit connections for including said resistance and contact finger in thecommon portion of the playing magnet circuit, and means for operating said contact finger comprising an electro-magnet included in a normally closed circuit arranged in parallel with the playing magnets and a spring acting in opposition to the pull of-said magnet.

8. An electrically-operated piano player comprising a series of playing magnets arranged in parallel branches of a circuit having a portion which is common to all the magnets of the series, means for closing the branch circuits through the several magnets according to the notes to be played thereby, a resistance divided into a number of portions, a segment bar having its segments connected with the resistance portions respectively, a contact finger movable along said bar, circuit connections for including said resistance and contact finger in the common ,portion of the playing magnet circuit, means for operating said contact finger comprising an electro-niagnet included in a normally closed circuit arranged in parallel with vthe playing magnets, and means for shifting said segment bar beneath the c011- tact finger.

In testimony whereof, I have hereunto subscribed my name this eighteenth day of January, 1913.

WALTER C. REED. W'itnesses E. D. CHADWICK, PHILIP N. Goewnr.

Copies of this patent may be obtained for five cents each, ,by addressing the Commissioner of Patents, Washington, D. C. 

